Previous studies in humans have indicated that functional obstruction of the Eustachian tube is an important factor in the pathogenesis of middle ear effusions. This type of obstruction appears to be related to the compliance of the tube or to an inefficient active tubal opening mechanism, or both. The purpose of this study is to establish an animal model from the experience gained in a pilot study in Rhesus monkeys (Macaca mulatta) in which the Eustachian tube was rendered functionally obstructed and the middle ear developed an effusion. In this investigation, functional Eustachian tube obstruction will be created by surgically altering the tensor veli palatini muscle. Normal and abnormal animals will be studied with specially developed manometric and tympanometric techniques. The recording method will hopefully be condensed into a single technique that can be used for the clinical evaluation of the human Eustachian tube. The overall objective is to gain further understanding of the structure and function of the Eustachian tube and of the varying circumstances which alter its function. With this approach it is hoped that a more rational and effective clinical management of the underlying causes of middle ear effusions will result.